Some electrophotographic image forming apparatuses include an intermediate transfer type image forming apparatus for primarily transferring a toner image from a plurality of image bearing members onto an intermediate transfer belt in a sequential overlapping manner, and then secondarily transferring the toner image from the intermediate transfer belt to a sheet of paper (see Patent Literature 1, for example). A color image forming apparatus displaces the intermediate transfer belt according to each of the operating states during monochrome image formation, during color image formation, and during non-image formation. The intermediate transfer belt is contacted only with an image bearing member for black color during the monochrome image formation, contacted with all of the image bearing members during the color image formation, and spaced away from all of the image bearing members during the non-image formation.
In conventional image forming apparatuses stated above, the meandering of the intermediate transfer belt may adversely affect the image quality during the image formation and, also during the non-image formation, may cause a widthwise end portion of the intermediate transfer belt to be bent by being strongly pressed against a flange portion of a stretching roller over which the intermediate transfer belt is stretched. Even during the non-image formation, when the widthwise end portion of the intermediate transfer belt bends, the image quality during image formation may be affected adversely. Therefore, it is important to suppress the meandering of the intermediate transfer belt.